The present invention concerns an alarm electronic watch which is able to control alarm time over a continual range and to automatically stop the alarm after a predetermined alarm duration.
In the prior art, there have been some methods used to stop operation of a watch alarm, either manually or automatically, after one minute from coincidence of present time and alarm time in order that the alarm setting time be different from the present time stored in a counting circuit. However, such an automatic alarm stopping mechanism was not adopted in practice, so that such kind of watch has been very inconvenient for users. Further, since the life of a watch battery is extremely shortened due to a high current, such as 10 mA, for one minute alarm operation if a buzzer is used, the foregoing technique could not be adopted for wrist watches. Another method defined the continual range of alarm duration by a time-constant of a capacitor and a resistance in an automatic alarm stopping mechanism, which requires a holding circuit separated from a time-counting system of a watch and requires a large value capacitor and additional discrete electronic parts added to an integrated timepiece circuit. Therefore it is inconvenient for use in a wrist watch and its continual range of alarm duration is varied by temperature change, so that it is unstable.